ArtooDetoo: Also, Menu/Settings/Applications/Manage Applications might let you delete the data and or app to fix it, in the unlikely event you haven't tried that.
I've checked through both the Downloaded and All tabs, but the "Retail Mode For Galaxy S2" app doesn't appear. I've also tried clearing the data for the Samsung Apps app, and it still thinks that there's an update for the app I don't have installed.
It might be a market-related issue. Based on the apps that appear, I think the software is thinks I'm in the Middle East. If I root I'll try Market Enabler to see if I can get other bits to appear.